The amount of UV radiation from the sun that reaches the surface of the earth varies around the globe and through time. Several factors account for this variation, e.g. cloud cover or ozone layer. UV (ultraviolet) radiation is light with wavelengths shorter than those visible to the human eye. UV radiation is divided into three categories by wavelengths: UVA (320-400 nm), UVB (290-320 nm) and UVC (100-290 nm). The wavelengths of UVA are longer than UVB and can penetrate deeper into the layers of our skin. UVA radiation contributes to skin aging, photochemical smog, fading and damage to woods, plastics, paints and fabrics. Only 1% of the solar radiation is within the UVB band, and most of this is blocked by the ozone layer. Nevertheless, UVB wavelengths are those that can cause the most damage to human skin. UVC radiation is totally blocked by the ozone and other gases in the atmosphere, and does not reach the surface of the earth.
UV radiation has both positive and negative effects. However, due to the negative impact that UV radiation sometimes has it is important to find solutions how to prevent the UV radiation to cause damages. The most common solution is to use UV blockers that will block the UV radiation and thus reduces the UV degradation of the exposed material. UV blockers are often used as additives in window films, in paints, coatings, plastic or plastic films, sunscreens and in paper or paperboard products. Components used as UVA/UVB blockers are e.g. avobenzone, oxybenzone, titanium dioxide and zinc oxide and they will prevent e.g. the skin or material from being negatively affected by the UV radiation. However, the UV blockers used today are both costly and might also have a negative effect on the environment or might not be approved for use in certain applications.
Thus, there is a need for a more environmental friendly and cost efficient UV blocker.